Phonograph



J. T. LEITCH.

PHONOGRAPH.

APPLICATION FILED APR.15,1921.

1,40 ,0 2, Patented Feb. 7, 1922.

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UNITED STATES PATENT OFFHJE- JAMES T. -LEITCH, OF ALLENTOWN, PENNSYLVANIA, ASSIGNOR OF TWO-FIFTHS TO TILGHMAN A. FREED AND EVA S. FREED, BOTH OF ALLENTOWN, PENNSYLVANIA.

PHONOGRAPH.

Application filed April 15, 1921.

To all whom it may concern:

Be it known that I, JAMES T. LEITCH, a citizen of the United States of America, residing at Allentown, in the county of Lehigh and State of Pennsylvania, have invented certain new and useful Improvements in Phonographs, of which the following is a specification.

This invention relates to phonographs and other like sound reproducing devices.

More especially the invention relates to an improved sound box for phonographs which I preferably term an articulator.

One important object of the invention is to provide an improved general construction of phonograph sound box.

A second important object of the invention is the provision, within the sound box of a perforated, floating and vibrating partition whereby to properly blend the tones and overtones and eliminate discordant sounds as well as to assist in increasing the volumes of produced sound.

With the above andother objects in view, the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings, and specifically claimed.

In the accompanying drawings, like characters of reference indicate like parts in the several views, said Fig. 1 is a section taken diametrically through the improved sound box.

Fig. 2 is a detail of the supplemental diaphragm.

In the embodiment of the invention herein illustrated there is provided a cylindrical casing 10 having on its front or face endan inturned flange 11. Within the casing and resting against this flange 11 is an elastic ring 12, which, in common with the other elastic rings hereinafter mentioned, is preferably made of rubber. Resting beneath this ring 12 is a ring 13 which has on one side a spaced pair of arms 14 terminating in hook shaped portions 15 and forming the fulcrum brackets as will be hereinafter explained. Below the fulcum bracket ring 13 is a second elastic ring 16 and against the Specification of Letters Patent.

Patented Feb. *7, 1922.

Serial No. 461,614.

under side of this ring bears the periphery of a sound diaphragm 17.

This diaphragm 17 consists of a disk of thin metal punched or otherwise formed to provide an exterior ring 18 from which extend radial fingers, the fingers lying in the same plane and having lanceolate inner extremities 19 connected to the ring 18 by narrow necks 20.

Beneath this diaphragm is an elastic ring 18 against the under side connected to a phonograph horn or the like. The ring 23 is held in position by a locking ring 25 screwed into the rear end of the casing 10.

From the foregoing it will be seen that the parts 13, 17 and 18 float resiliently in the casing by reason of their being supported on the rubber rings and that the back is also floatingly connected to the casing.

The operation of this sound box is as follows. The vibration of the diaphragm 17 sets up waves in the air between the diaphragm 17 and the fingers 19. These waves are broken up and passed through the openings between the said fingers. At the same time the fingers themselves are thrown into vibration and the effect thus produced in the space between the fingers 19 and the back plate 23 is a combination of the wave efi'ect passing through the openings and supplemental wave efl'ect produced by the vibration in said fingers. In practice it has been found that the characteristic overtone which distinguishes one instrument or voice from another are produced by this means in a precise and faithful manner.

There has thus been provided a highly efficient device of the kind described and for the purpose specified.

It is obvious that many minor changes may be made in the form and construction of the invention without departing from the principles thereof. It is not, therefore, desired to confine the invention to the exact form herein shown and described, but it is wished to include all such as properly come within scope claimed. 7

Having thus described the invention, what is claimed as new, is

1. In a phonographic reproducer, a sound 3. In a phonographic reproducer, a sound box having a perforated partition therein 10 consisting of an exterior rin and inwardly directed radial fingers, said ngers all lying in the same plane. 7 s Q 7 a In testimony whereof I affix my signature.

" JAMES T. L-ErToH. 

